Patent EA-001304-B1 (EA)
Title: Oil recovery method using an emulsion
Inventor: BRAGG JAMES R
IPC: C09K8/26
Filed: 1998-05-14
Abstract: 1. A solids-stabilized emulsion for use in recovering hydrocarbons from a porous subterranean formation, said emulsion comprising: (a) a first liquid; (b) droplets of a second liquid suspended in said first liquid, the average diameter of said droplets being smaller than the average diameter of the pore throats in said porous subterranean formation; and (c) solid particles which are insoluble in both said first liquid and said second liquid at the conditions of said subterranean formation, the average particle size of said solid particles being less than or equal to said average droplet diameter. 2. The solids-stabilized emulsion of claim 1, wherein said average particle size of said solid particles is less than about one-half of said average droplet diameter. 3. The solids-stabilized emulsion of claim 1, wherein the ratio of said average particle size to said average droplet diameter ranges from about 0.001 to about 1. 4. The solids-stabilized emulsion of claim 1, claim 2, or claim 3, wherein said average droplet diameter is less than about 30 microns. 5. The solids-stabilized emulsion of claim 1, claim 2, or claim 3, wherein said average droplet diameter is less than about 15 microns. 6. The solids-stabilized emulsion of claim 1, claim 2, or claim 3, wherein said average particle size is less than about 10 microns. 7. The solids-stabilized emulsion of claim 1, claim 2, or claim 3, wherein said average particle size is less than about 2 microns. 8. The solids-stabilized emulsion of claim 1, claim 2, or claim 3, wherein said first liquid is oil, said second liquid is water, and said solid particles are at least partially oleophilic. 9. The solids-stabilized emulsion of claim 8, wherein water comprises at least sixty volume percent of said solids-stabilized emulsion. 10. The solids-stabilized emulsion of claim 1, claim 2, or claim 3, wherein said first liquid is water, said second liquid is oil, and said solid particles are at least partially hydrophilic. 11. The solids-stabilized emulsion of claim 1, claim 2, or claim 3, wherein said solid particles are selected from the group consisting of clays, quartz, feldspar, gypsum, coal dust, asphaltenes, and polymers. 12. The solids-stabilized emulsion of claim 1, claim 2, or claim 3, wherein said solid particles comprise fundamental particles of bentonite clays. 13. The solids-stabilized emulsion of claim 1, claim 2, or claim 3, wherein said solid particles comprise kaolinite clays. 14. The solids-stabilized emulsion of claim 1, claim 2, or claim 3, wherein said solid particles comprise fumed silica. 15. The solids-stabilized emulsion of claim 1, wherein said solids-stabilized emulsion further comprises a gas. 16. The solids-stabilized emulsion of claim 15, wherein said solids-stabilized emulsion contains a sufficient amount of gas to reduce the viscosity of said solids-stabilized emulsion to less that about ten times the viscosity of said hydrocarbons. 17. The solids-stabilized emulsion of claim 15, wherein said solids-stabilized emulsion contains a sufficient amount of gas to increase the mobility of said solids-stabilized emulsion to a point approximately equal to, but not greater than, the mobility of said hydrocarbons. 18. The solids-stabilized emulsion of claim 15, claim 16, or claim 17, wherein said gas is selected from the group consisting of carbon dioxide, sulfur dioxide, and hydrocarbon gases. 19. A method for recovering hydrocarbons from a porous subterranean formation, said method comprising the steps of: (a) making a solids-stabilized emulsion containing (1) a first liquid, (2) droplets of a second liquid suspended in said first liquid, the average diameter of said droplets being smaller than the average diameter of pore throats in said porous subterranean formation, and (3) solid particles which are insoluble in both said first liquid and said second liquid at the conditions of said subterranean formation, the average particle size of said solid particles being less than or equal to said average droplet diameter; (b) injecting said solids-stabilized emulsion into said subterranean formation; and (c) recovering said hydrocarbons from said subterranean formation. 20. The method of claim 19, wherein said solids-stabilized emulsion is used to form a flow barrier for diverting flow of said hydrocarbons in said subterranean formation. 21. The method of claim 20, wherein said solids-stabilized emulsion is injected into a high permeability thief zone of said subterranean formation to prevent said hydrocarbons from entering said thief zone. 22. The method of claim 20, wherein said solids-stabilized emulsion is used to create a horizontal barrier to vertical flow of oil or gas to reduce coning of said oil or gas into a hydrocarbon producing zone. 23. The method of claim 19, wherein said solids-stabilized emulsion is used as a drive fluid to displace said hydrocarbons from said porous subterranean formation. 24. The method of claim 19, claim 20, claim 21, claim 22, or claim 23, wherein said first liquid is oil, said second liquid is water, and said solid particles are at least partially oleophilic. 25. The method of claim 19, claim 20, claim 21, claim 22, or claim 23, wherein said first liquid is water, said second liquid is oil, and said solid particles are at least partially hydrophilic. 26. The method of claim 19, claim 20, claim 21, claim 22, or claim 23, wherein said solid particles are selected from the group consisting of clays, quartz, feldspar, gypsum, coal dust, asphaltenes, and polymers. 27. The method of claim 19, wherein said solids-stabilized emulsion further contains a gas. 28. The method of claim 27, wherein said solids-stabilized emulsion contains a sufficient amount of gas to reduce the viscosity of said solids-stabilized emulsion to less than about ten times the viscosity of said hydrocarbons. 29. The method of claim 27, wherein said solids-stabilized emulsion contains a sufficient amount of gas to increase the mobility of said solids-stabilized emulsion to a point approximately equal to, but not greater than, the mobility of said hydrocarbons. 30. The method of claim 27, claim 28, or claim 29, wherein said gas is selected from the group consisting of carbon dioxide, sulfur dioxide, and hydrocarbon gases. 31. A method for making an emulsion for use in recovering hydrocarbons from a porous subterranean formation, said method comprising the steps of: (a) selecting a first liquid and a second liquid for use in said emulsion; (b) selecting a type of solid particles to be used to stabilize said emulsion, said solid particles being insoluble in both said first liquid and said second liquid at the conditions of said porous subterranean formation, the average particle size of said solid particles being smaller than the average diameter of the pore throats in said porous subterranean formation; (c) combining said first liquid, said liquid, and said solid particles to make a mixture thereof; and (d) shearing said mixture to produce an emulsion of droplets of said second liquid suspended in said first liquid and continuing said shearing until the average diameter of said droplets is smaller than the average diameter of said pore throats in said porous subterranean formation; (e) whereby said solid particles stabilize said emulsion by preventing coalescence of said droplets of said second liquid. 32. The method of claim 31, wherein said method further comprises the step of adding a gas to said mixture. 33. The method of claim 32, wherein a sufficient amount of gas is added to said mixture to reduce the viscosity of said emulsion to less than about ten times the viscosity of said hydrocarbons. 34. The method of claim 32, wherein a sufficient amount of gas is added to said mixture such that the mobility of said emulsion is increased to a point approximately equal to, but not greater than, the mobility of said hydrocarbons. 35. The method of claim 32, claim 33, or claim 34, wherein said gas is selected from the group consisting of carbon dioxide, sulfur dioxide, and hydrocarbon gases. 36. The method of claim 32, claim 33, or claim 34, wherein said gas is added to said mixture prior to said step of shearing said mixture. 37. The method of claim 32, claim 33, or claim 34, wherein said gas is added to said mixture after said step of shearing said mixture. 38. The method of claim 31, wherein said step of combining said first liquid, said second liquid, and said solid particles comprises first mixing said solid particles into said first liquid and then adding said second liquid. 39. The method of claim 31, claim 32, claim 33, or claim 34, wherein said first liquid is oil, said second liquid is water, and said solid particles are at least partially oleophilic. 40. The method of claim 39, said method further comprising the step of preconditioning said solid particles prior to making said mixture to make said solid particles at least partially oleophilic. 41. The method of claim 31, claim 32, claim 33, or claim 34, wherein said first liquid is water, said second liquid is oil, and said solid particles are at least partially hydrophilic. 42. The method of claim 41, said method further comprising the step of preconditioning said solid particles prior to making said mixture to make said solid particles at least partially hydrophilic. 43. The method of claim 31, claim 32, claim 33, or claim 34, wherein said solid particles are selected from the group consisting of clays, quartz, feldspar, gypsum, coal dust, asphaltenes, and polymers. 44. The method of claim 31, claim 32, claim 33, or claim 34, wherein said solid particles comprise fundamental particles of bentonite clays. 45. The method of claim 31, claim 32, claim 33, or claim 34, wherein said solid particles comprise particles of kaolinite clays. 46. The method of claim 31, claim 32, claim 33, or claim 34, wherein said solid particles comprise fumed silica.